Organic electroluminescent device, method for fabricating the same, and light emitting apparatus

Abstract

An organic electroluminescent device, a method for fabricating the same, and a light emitting apparatus are disclosed. The organic electroluminescent device comprises a first light emitting layer and a second light emitting layer arranged on a surface of the first light emitting layer at a first side, and partially covers the surface of the first light emitting layer at the first side. Both the first and second light emitting layers are made from a material which has a larger mobility for a first carrier than a second carrier. Light emitting regions of the second light emitting layer and the regions of the first light emitting layer not covered by the second light emitting layer are configured to emit light of different colors at a preset light emitting ratio. A light emitting area ratio between a surface of each light emitting region and surfaces of the regions of the first light emitting layer not covered by the second light emitting layer is preset according to the preset light emitting ratio.

What is claimed is: 
     
       1. An organic electroluminescent device, comprising a first light emitting layer and a second light emitting layer, the first light emitting layer and the second light emitting layer being in direct contact,
 wherein the second light emitting layer is arranged on a surface of the first light emitting layer at a first side, and partially covers the surface of the first light emitting layer at the first side; 
 wherein both the first light emitting layer and the second light emitting layer are made from a material which has a larger mobility for a first carrier than a second carrier; 
 wherein the second light emitting layer comprises at least one light emitting region, each light emitting region of the second light emitting layer and regions of the first light emitting layer not covered by the second light emitting layer are configured to emit light of different colors at a preset light emitting ratio, light emitted from an overlapping area of the first light emitting layer and the second light emitting layer presents a light emitting color of the light emitting region of the second light emitting layer, and in each of the light emitting units of the organic electroluminescent device, a light emitting area ratio between a surface of each light emitting region and surfaces of the regions of the first light emitting layer not covered by the second light emitting layer is preset according to the preset light emitting ratio; 
 wherein the second light emitting layer comprises a first organic material layer and a second organic material layer, at least a portion of the first organic material layer forms a first light emitting region among the at least one light emitting region, and at least a portion of the second organic material layer forms a second light emitting region among the at least one light emitting region; 
 wherein a surface of the first light emitting layer at a second side is configured to receive the first carrier, and a surface of the second light emitting layer away from the first light emitting layer and the surfaces of the regions of the first light emitting layer not covered by the second light emitting layer are configured to receive the second carrier; and 
 wherein the first light emitting layer covers at least two adjacent light emitting units and the area between the adjacent at least two light emitting units, the adjacent light emitting units are respectively covered by the corresponding second light emitting layer, and the second light emitting layer is disconnected in the area between the adjacent light emitting units. 
 
     
     
       2. The organic electroluminescent device of  claim 1 , wherein each light emitting region of the second light emitting layer and the regions of the first light emitting layer not covered by the second light emitting layer are configured to emit light at the preset light emitting ratio, so that the emitted light is mixed into white light. 
     
     
       3. The organic electroluminescent device of  claim 1 , wherein the first organic material layer and the second organic material layer are arranged side by side on the surface of the first light emitting layer at the first side, and partially cover the surface of the first light emitting layer at the first side; and
 wherein the first organic material layer forms the first light emitting region, and the second organic material layer forms the second light emitting region. 
 
     
     
       4. The organic electroluminescent device of  claim 1 , wherein the first organic material layer is arranged on the surface of the first light emitting layer at the first side, and partially covers the surface of the first light emitting layer at the first side;
 wherein the second organic material layer is arranged on a surface at a side of the first organic material layer away from the first light emitting layer, and partially covers the surface at the side of the first organic material layer away from the first light emitting layer; and 
 wherein a region of the first organic material layer not covered by the second organic material layer forms the first light emitting region, and the second organic material layer forms the second light emitting region. 
 
     
     
       5. The organic electroluminescent device of  claim 4 , wherein the second light emitting layer further comprises a third organic material layer, the third organic material layer and the first organic material layer are arranged side by side on the surface of the first light emitting layer at the first side, and the third organic material layer form a third light emitting region. 
     
     
       6. The organic electroluminescent device of  claim 1 , wherein in each of the light emitting units of the organic electroluminescent device, a light emitting area ratio between each light emitting region and the regions of the first light emitting layer not covered by the second light emitting layer is larger than 1. 
     
     
       7. The organic electroluminescent device of  claim 1 , wherein the first light emitting layer is an integral structure in the light emitting region of the organic electroluminescent device. 
     
     
       8. The organic electroluminescent device of  claim 1 , further comprising a first electrode layer and a second electrode layer, wherein both the first light emitting layer and the second light emitting layer are arranged between the first electrode layer and the second electrode layer. 
     
     
       9. The organic electroluminescent device of  claim 8 , wherein the first electrode layer or the second electrode layer is an integral structure in the light emitting region of the organic electroluminescent device. 
     
     
       10. The organic electroluminescent device of  claim 1 , further comprising:
 a first carrier transport layer, which is arranged to contact the surface of the first light emitting layer at the second side; 
 a first carrier inject layer, which is arranged at a side of the first carrier transport layer away from the first light emitting layer; 
 a second carrier transport layer, which is arranged to contact the surface of the second light emitting layer away from the first light emitting layer and the surface of the first light emitting layer at the first side not covered by the second light emitting layer; and 
 a second carrier inject layer, which is arranged at a side of the second carrier transport layer away from the second light emitting layer and the first light emitting layer. 
 
     
     
       11. The organic electroluminescent device of  claim 1 , wherein the first carrier is hole, and the second carrier is electron. 
     
     
       12. A light emitting apparatus, comprising the organic electroluminescent device of  claim 1 . 
     
     
       13. A method for fabricating the organic electroluminescent device of  claim 1 , comprising: forming the first light emitting layer and the second light emitting layer, wherein the second light emitting layer is arranged on the surface of the first light emitting layer at the first side, and partially covers the surface of the first light emitting layer at the first side;
 wherein during forming the second light emitting layer, the method comprises: 
 by using a fine metal mask, forming organic material layers in sequence in each of the light emitting units which correspond to each light emitting region, wherein an opening ratio of each of the organic material layers is determined by a preset light emitting area ratio between the light emitting region to which said organic material layer corresponds and the surfaces of the regions of the first light emitting layer not covered by the second light emitting layer. 
 
     
     
       14. The method of  claim 13 , comprising forming the first light emitting layer by using an open mask. 
     
     
       15. The organic electroluminescent device of  claim 1 , wherein a ratio between an area of the surface of the first light emitting layer at the first side covered by the second light emitting layer and an area of the uncovered surface of the first light emitting layer at the first side is 3:1; the first light emitting layer is a blue fluorescent material layer, and the second light emitting layer is a yellow fluorescent material layer.